The processing of biomass and biomass-derived materials is often undertaken with the objective of chemical or biochemical processing to yield fuels and or chemicals (often referred to as “biofuels” or “biochemicals”). Initial processing steps toward this objective typically include hydration and hydrolysis to yield sugars or sugars-rich intermediates; this transformation is also referred to as “saccharification”.
Material and energy efficiencies of the hydration and hydrolysis steps are often largely determined by the preprocessing and pretreatment of the biomass material, which typically begins in its solid-phase physical state. These efficiencies are directly impacted by solid particle size and size distributions, effectiveness of dispersion of the solid mass in concert with its mixing and wetting with added water (“hydration”), and the degree to which this two-phase mixture can be homogenized and transported in this state to downstream unit operations. In addition, it is usually advantageous—provided the above conditions can be maintained—to maximize the practically achievable solids content in the resultant two-phase slurry mixture. This attribute establishes increased intensity of chemical and or biochemical reactions downstream, in turn enabling reduced capital cost in those unit operations—as well as reduced energy costs associated with subsequent product separations and water recovery.
The prior art includes a variety of dispersing and mixing devices and techniques including those defined by Medoff in U.S. Pat. No. 8,420,356 B2 and U.S. application Ser. No. 13/789,102 and U.S. Ser. No. 14/224,340 in which a lignocellulosic feedstock is saccharified or liquefied into monomeric sugars utilizing a dispersing system to dispense the fibrous feedstock in the recycle loop of a batch saccharification process at high solids loadings.
Some strategically important biomass materials—notably corn stover and sugarcane bagasse—tend to be of low density in dry transport, as well as resistant (recalcitrant) to hydration. For these materials, it is desired to achieve effective and efficient mixing with water, hydration (including thorough wetting), and high-solids homogeneous slurries. The present invention facilitates the generation of these slurries for the objectives of biofuels and or biochemical production—particularly in the application of these challenging, yet strategically important feedstock classes.